<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <div id="app"></div>
  <template id="my-app">
    <h2 v-html="message"></h2>
  </template>
  <script src="./assets/js/vue.js"></script>
  <script>
    const app = Vue.createApp({
      template: '#my-app',
      data() {
        return {
          message: '<span style="color:red; font- size:30px">Hello</span>'
        }
      },
      methods: {

      }
    })
    app.mount("#app")
  </script>
</body>

</html>